Heat transfer device



Nov. 14, 1933.

B. L. QUARNSTROM HEAT TRANSFER DEVICE 3 Sheets-Sheet 1 Filed Sept. 13,1932 INVENTOR. 62W? 1,. QUfi/FMSTIFOM- 1 ATTORNEYS.

Nov. 14, 1933. B. 1.. QUARNSTROM HEAT TRANSFER DEVICE Filed Sept. 15,1932 3 Sheets-Sheet 2 INVENTOR. 567? 7' L 001mm: TRON. f?

ATTORNEYS.

NOV. 14, 1933- QUARNSTRQM 1,935,332

HEAT TRANSFER DEVICE Filed Sept. 13, 1932 5 Sheets-Sheet 3 INVENTOR.55191 L (Pu/2mm 7mm.

ATTO

Patented Nov. 14,1933- HEAT TRANSFER DEVICE Bert L. Quarnstrom, Detroit,Mich., assignor to Bundy Tubing Company, Detroit, Mich., a corporationof Michigan Application September 13, 1932 Serial No. 632,971

23 Claims.

This invention relates to a heat transfer device which may be employedas a condenser for mechanical refrigerators; as a core for the radiatorof an automotive vehicle, airplane, lighter than aircraft, stationaryinternal combustion engine,

or the like; as a device for regulating the temperature of lubricatingoil of an engine; as the radiator element of a hot water heater for automobiles and the like; or for-general heating and cooling purposes inbuildings. This application is a continuation in part of my priorapplication Serial No. 626,760, filed July 30, 1932.

The permissible height and width of an automobile radiator are limitedby considerations such as size of the vehicle, wind resistance,appearance, and stream-lining at the front end of the vehicle.Accordingly it has been proposed to obtain greater radiating area andcooling capacity by increasing the dimensions of the radiator at rightangles to its plane, which dimension may be termed the depth of theradiator. It is well known however that the cooling efficiency at therear of the radiator is far less than at the front of the radiator sothat the increase in cooling effect that can be obtained in this way islimited. Various means such as baflles have additionally been employed,without, however, affecting in any way the fact as stated above thatthegreatest cooling efiect is obtained at the front of the radiatorwhile the water at the rear of the radiator is cooled only slightly.Hence it has heretofore been impracticable to reduce 'the frontal areaof an automobile radiator to the desired extent or to obtain highcooling efiiciency for a radiator of a'given size.

In heat transfer devices embodying the present invention, the heattransfer eificiency throughout the device is equalized so that theentire body of a fluid circulating through the device is substantiallyequally affected, either by cooling or by heating the same as the casemay be. For example, in contrast with automobile radiators of the tubetypeand the cellular type, an automobile radiator embodying the presentinvention provides that the entire body of water flowing through thedevice follows the same or a substantially parallel heat transfer pathand is equally cooled throughout. To this end a plurality of streams ofwater, instead of flowing downwardly each in substantially the samevertical direction from top to bottom as in the tube and cellular types,are each caused to -flow horizontally back and forth in the direction ofthe depth of the radiator and throughout substantially its entire depth.It will be understood that each reversal of flow takes place at a lowerlevel so that each stream gradually moves downwardly in a generallyvertical direction, following what may be describe specificallyas ahorizontal path alternately reversed indirection. The result is that thestreams of water pass through heat transfer paths that are the same asto cooling effect for all streams, and that the body of water in eachstream moves back and forth between the front and back of the radiatorand is broken up and thoroughly mixed by reversing its direction offlow, so that the cooling efficiency of the radiator is equalized fromfront to back of the radiator and all parts of the body of water areequally cooled.

Another factor of importance in the design of an efficient heat transferdevice is to provide a large total heat transfer area of material ofhigh heat conductivity in order to obtain an efficient transfer of heatbetween the two fluids. In a radiator or other heat transfer deviceembodying the present invention, a multiplicityof streams of smallcross-sectional area are provided, the structure forming these tubesproviding a large external radiating fin areaand the path beingrelatively long so that the cooling effect is increased. -Moreover, thehorizontal partitions be tween adjacent reversely directed portions ofeach stream constitute internal fins of large area which conduct theheat out of the water and to the cooling air. These internal fins can beformed integrally with the external radiating fins as describedhereinafter so that the heat does not have to be conducted acrosssoldered, welded, or other joints.

Tests have shown that a heat transfer device of the new type describedgenerally above, and more particularly hereinafter, when employed forexample as an automobile radiator, is remarkably more efiicient thanautomobile radiators heretofore used, the K value being in cases testedas much as 50% and more above the K value of prior radiators. This meansthat the size of the radiator (or other heat transfer device) can becorrespondingly reduced with a resultant saving in material and cost.Furthermore, in the case of vehicles the frontal area of the radiatorcan be reduced to permit stream-lining, a result hitherto made difiicultby the requirement for a large frontal radiator area as determined byprevious standards of cooling efficiency.

Hence it is an object of the invention to provide a novel heat transferdevice suitable for use as a radiator and for other purposes which is ofsuch design that the above described operation is carried out and theresults of equalized heat transfer efiiciency together with thoroughmixing of the streams of fluid and equal cooling or heating of all partsthereof are attained.

A further object is to provide a novelheat transfer device wherein theheat transfer eflillO ciency as determined by the K value of the deviceis greatly increased, whereby the size of the device required for anyparticular purpose can be reduced.

A further object is to provide a novel heat transfer device wherein thetortuous paths described 'above are provided without the formation ofpockets or obstructions to thefiow through the device.

A still further object is to provide a device of the class describedwherein corrosion is prevented by a non-corrodible material.

Another object is to provide a novel heat transf er device which isimproved from the standpoints of mechanical strength, liability todevelopment of leaks, and ease, flexibility and economy of manufacture.

Generally speaking, the core of a heat transfer device embodying theinvention can be constructed in any suitable way. Preferably, however, amultiplicity of core elements are provided, each comprising a strip ofmaterial having a. width equal tothe depth of the core and having aplurality of trough-like depressions extending transversely of the stripand formed by casting, stamping, drawing, etc. Preferably also thesecore elements are integral and are each formed of a single piece ofmetal having good heat conduc-- 'tivity, such as iron or steel,aluminum, copper,

brass, etc. When the core elements are assembled as hereinafterdescribed to form the core, they may be secured together in fluid-tightrelation in any suitable way such as soldering, welding or in some casesmerely by pressing them together. The specific method may dependsomewhat on the material used; for example, cast aluminum core elementsare most conveniently soldered together, whereas copper and brass coreelements are soldered or brazed. Excellent results have been obtained bystamping the depressions in copper coated steel strips and welding theelements together by the copper hydrogen welding process, this methodproviding core elements having the structural strength of the steelstrips with the corrosion resisting qualities of copper, the elementsbeing welded together and the copper being alloyed to the steel so thatthe joints are perfectly fluid-tight and almost as strong as the steelitself. Furthermore, a core comprising a stack or series of stacks oftroughs can be cast as an integral unit of any desired or suitablemetal.

' In such a device embodying the invention one fluid enters at the topof the transfer device and passes out at the bottom, flowing through thenumerous chambers which .are afforded by the juxtapositioned trough-likedepressions which are disposed horizontally and extend from a point nearthe front surface of the device to a point near the rear surface of thedevice.

The drawings show several embodiments of the invention as illustrationsof the many uses of the invention enumerated above. It is to beexpressly understood, however, that the invention is not limited eitherto these particular uses or to the specific structural embodimentsillustrated and that the drawings are not to be construed as adefinition of the limits of the invention, reference being had to theappended claims for this purpose.

In the drawings:

Fig. 1 is a side elevational view of a radiator structure embodying theinvention with some parts cut away and some parts in section;

menace Fig. 2 is an end view with some parts cut away and some insection;

Fig. '3 is an enlarged sectional view taken on line 3-3 of Fig. 4;

Fig. 4 is an enlarged sectional view at right angles to that of Fig. 3and taken on line 4-4 of Fig. 3;

Fig. 5 is a perspective view of a portion of a core element showing thetrough formations;

Fig. 6 is a sectional view similar to that of Fig. 4 illustrating amodified structure in which the invention is embodied;

Fig. 7 is a sectional view illustrating a modified form of headerstructure;

Fig. 8 is a side elevational view with parts cut away and parts insection illustrating a core of a radiator for an automotive or othervehicle;

Fig. 9 is a front elevational view thereof, illustrating the modifiedform of core element;

Fig. 10 is an enlarged sectional view illustrating a modified form oftrough for obtaining the gravity drain;

Fig. 11 is a View taken substantially on line 1l11 of Fig. 10;

Fig. 12 is a sectional view illustrating a form with modified troughdimensions;

Fig. 13 is a fragmentary plan view of one of the trough membersillustrated in Fig. 12;

Fig. 14 is a sectional view taken substantially on line i l-14 of Fig.12;

Fig. 15 is an enlarged sectional view illustrating troughs made fromindividual plates, as also shown in Fig. 9.

Fig. 16 is a sectional view taken through a radiator structure in theform of a casting.

Fig. 17 is a view partly in section and partly in side elevation lookingon line 1717 of Fig. 16 showing two cast sections connected.

Fig. 18 is a sectional view taken on line 18-18 of Fig. 16.

First referring to Fig. 5, a core element is illustrated at 1, the samebeing relatively long and narrow, and positioned crosswise of the stripand substantially parallel to each other are troughs 2. These troughsare shown in cross section in Figs. 3 and 4 and each has end walls 3 and4 (Fig. 4), side walls 5 and 6 (Fig. 3), and a bottom wall 7. Thesetroughs may be provided in any suitable way; where the elements 1 are ofsheet metal, a simple stamping operation is preferred, either in theform of a single die operation where the metal will withstand thedrawing and thinning, or of two or more successive die operations whereit is desirable to lessen the thinning and drawing of the metal. 1

as illustrated at 12, provides additional fin areas.

A suitable number of core elements thus formed are disposed injuxtaposition preferably in superimposed relation with the troughs ofone element fitting into the troughs of the next adjacent element, asillustrated. The walls 3 and 4 are preferably inclined, as are also thewalls 5 and 6, so that the troughs are of tapering formation with thebottom of each trough of smaller overall of the lowermost core element.

dimensions than its open top. Accordingly, a plurality of the elementsmaybe superimposed and pressed tightly together so that the troughs onjuxtapositioned elements tightly fit into each other. Once assembled,the core elements can be secured together and the engagement between theinterfitting troughs can be made fluid-tight in any suitable way. Insome instances it will sufiice merely to press the elements tightlytogether and hold them by clamps or tie rods. It is generallypreferable, however, to solder, braze or weld the elements together,more particularly at their contacting trough portions. Good welded orsoldered joints' will generally form sufficient mechanical connectionbetween the elements, although clamps, tie rods or any suitableframework can be employed in addition.

Prior to the assembling of the elements, apertures 13 are provided inthe bottoms of the troughs in any suitable way as by a punch operation:While all of the core elements, save perhaps the lowermost anduppermost, in the complete assembly are substantialy identical, everyother one is reversed end for end to locate the apertures 13 of adjacenttroughs at opposite ends of a chamber formed by the trough formations.The walls of each two adjacent troughs provide a chamber between them,as illustrated at 14, and fluid passes through one aperture 13 leadinginto this chamber and then horizontally through the chamber 14 and outthrough the aperture 13 at the other end. The fluid then reverses itshorizontal flow through the next lower chamber, and so on through theentire structure. The portions 12 cooperate as illustrated in Fig. 3 toprovide passageways 15 for another fluid.

As clearly shown in Fig. 4, the bottom 7 of each.

trough may be inclined from its unapertured end toward its aperturedend, this being accomplished during the stamping, casting or otherforming operation by making one end wall 4 of each trough longer ordeeper than the other end wall 3. This construction provides a gravitydrain throughout the core and avoids the formation of pockets in whichthe circulating fluid might be trapped or deposits of dirt, sediment,etc., might accumulate. In this connection it should be noted that theflow area of the apertures 13, while preferably as great as the meanflow area of the passages or chambers 14, may, if desired, be madesmaller so as to constrict the flow through a part or all of the devicewithout interfering in any way with the uniformity of size of the coreelements, the radiating area of the device, or

other characteristics thereof.

In the form shown, a header cap plate19 is utilized at the top of thedevice and is suitably shaped to provide a header chamber 20, and thetopmost core element is of such dimensions as to provide sufficientmetal to be fashioned over the edges of the header plate, as illustratedat 21. A suitable conduit connection, as shown at 23, is provided toconduct fluid to or from the device.

A header of any suitable type is provided at the lower end of thestructure, and as shown it comprises a header plate 24 having suitableapertures formed therein for the reception of the troughs Theseapertures are illustrated at 25 and are advantageously defined byflanges 26 which embrace the outside of the troughs of the lowermostsheet metal element. A base plate 2'7 is fashioned to provide a shoulder28, and the header plate 24 has its edge portions flanged as at 29 forfitting against the shoulder 28, and the header plate 24 may have itsedge portions flanged as at 29 for fitting againstthe shoulder 28. Asuitable conduit 30 may be connected into the header chamber 31 providedby the header plate 24 and base plate 27.

In the operation of such a heat exchange device it may be assumed thatthe particular device shown is for use as a condenser for a refrigerantwhich enters through the conduit 23 and passes into chamber 20. Thefluid then passes in a plurality of streams through the troughs. Eachstream passes substantially horizontally first to the right and then tothe left, as Fig. 4 is viewed, finally passing through the structurefrom the uppermost header to the lower header space 31, and thence outthe conduit 30. Air may be blown or drawn through the device by asuitable fan or blower, ,if such is desired, and such air contacts withthe fins or areas 10 and 11 and passes through the passageways 15 thushaving intimate contact with the heat dissipating portions 12 and withthe side walls 5 and 6 of the troughs. cordingly, a very extensiveintegral heat exchange area is afforded thus making the device a,particularly efficient one for heat transfer.

The device shown in Fig. 6 comprises essentially the same structure asthat heretofore described -and the same reference characters are appliedthereto, thus eliminating duplicate description. This device illustrateshow the troughs may be materially increased in length, thus providinglonger horizontal passageways for the flow of fluid therethrough. Thisincreased length may be desired in some instances where an increase inheat transfer area is wanted.

A modified form of header structure is shown in Fig. 7. The plates withthe trough formations are illustrated at 40 with their aperturesdisposed in accordance with the disposition of the apertures in theforegoing forms. The header comprises a cap plate 41 and another plate42, the edges of one being fashioned over the other. In the formillustrated the edges 43 of the plate 41 are fashioned over the edges ofplate 42, forming a header chamber 44 to which is connected a conduit45. The plate 42 has apertures therein for receiving the trough-likeformations of the top.

plate 40 so that the edges of the two uppermost plates may engageopposite sides of the plate 42 as shown. The topmost plate 40 may bedisposed generally above the plate 42 with its troughs extending throughthe apertures in plate 42, and the next lower plate may be fitted to thetroughs of the topmost plate.

In Figs. 8 and 9 there is shown the core of a radiator for anautomobile, aircraft or any other walls of which all extend a uniformdistance from the plates 53 as distinguished from the form shown in Fig.4 wherein one end wall 4 extends farther fromthe plate 1 than the otherend wall 3 in order to provide the desired inclination of the bottoms '7for the' purpose of gravity drain. As shown in Figs. 10 and 11, theinclination of the bottoms of the troughs 54 is provided by depressingeach bottom out of its normal plane as illustrated at 55, the depressedportions inclining toward the ends of the troughs in which the apertures56 are formed and appearing as illustrated in Fig. 11. While Figs. 8 and9 show a radiator having troughs of the form illustrated in Figs. 10 and11, they may employ the trough arrangement illustrated in Figs. 3 and d.

In the form shown in Figs. 12, 13 and 14, the troughs 57 are somewhatlonger and narrower than in the preceding forms, the depressed portions58 of the trough bottoms extending the 811-- tire width of the troughbottoms and having arc'uate cross sections which merge smoothly into thelower edges of the side walls of the troughs. The apertures 59 alsoextend the entire width of the trough bottoms and are elongated in thedirection of the length of the troughs until their flow area issubstantially equal to the mean flow area of the troughs 57. If desired,however, the flow through all or part of the device may be restricted bydecreasing the elongation of the apertures 59. As shown in Fig.13, noshoulders or constrictions are left around the apertures at the ends ofthe troughs, the fluid draining freely therethrough and from the arcuatelips formed by the ends of the depressed portions 58 of the troughbottoms. This form of trough can be substituted for either of thosedescribed above whenever desired.

Instead of providing a plurality of troughs in a single integral coreelement, each trough can be formed in an individual sheet or plate ofmetal as illustrated in Fig. 15. This Figure 15 shows an enlargedsectional view of such an arrangement wherein each vertical row ofchambers formed by the troughs is provided by a stack of separate platesor sheets 60 each having one trough 61 formed therein. The severalstacks may be placed in close proximity preferably with their'edgesslightly spaced as shown. This structure permits of disposing thetroughs in closer relation than is feasible where the troughs are formedin one sheet of metal so that formed in one sheet there must be somespacing between them in order to provide metal for the formingoperation, particularly where sufficient metal must be provided for agathering action. Moreover, this method of making and assembling thecore structure provides great flexibility of manufacture, since theplates 60 can be made up in quantities and assembled as desired intocores of widely varying types and sizes. Where individual sheets orplates are used they may be trimmed as desired either before or afterthe formation of the trough. In disposing the troughs formed ofindividual plates in close proximity, the fin area is reduced and theamount of fin area required may determine the spacing between thetroughs. It will be observed that a radiating fin 62 is provided aroundthe troughs in the individual plates, and that an additional radiatingarea is aiforded by the edges of each plate.

In such a structure, particularly where there is a considerable flow ofliquid through the chambers formed thereby, it is preferred that theflow of liquid therethrough be fairly uniform. In this connection thesize or area of the apertures in the bottoms of the troughs arepreferably such as substantially to correspond to the cross sectionalarea or flow area of the chambers formed by the troughs. For this reasonthe elongated aperture of Figs. 12 and 13 may be employed where thetrough is relatively narrow in which case a circular aperture having adiameter equal to the width of the trough would not provide sufficientflow. Obviously, where the bottoms of the troughs are inclined thechambers formed thereby are not of uniform cross sectional area, and insuch a case the area of the apertures may correspond substantially tothe mean flow area of the chambers. However, as indicated above it maybe desirable in some'cases to employ apertures which have a flow arealess than the mean flow area of the chambers. In this way the flowthrough a heat transfer device of any given size and type can berestricted as desired, and also the how through one part of the devicecan be restricted as regards the flow through another part of thedevice. Attention is also called to the fact that the device is soconstructed as to avoid the formation of pockets in which the fluid orsolid matter carried thereby could be trapped. This is due to theinclined bottoms of the troughs and the apertures extendingsubstantially the width of the trough bottoms, whereby continuousuninterrupted flow through the device is obtained. The speed of flow ofa fluid through the device can be regulated by varying the pitch orinclination of the trough bottoms and the size of the apertures.

The various elements going into the structure, particularly the coreelements with the troughs and the header plates, are generally to bejoined This may be done by uniting the various elements where theycontact with each other by 195 sealing them together with any suitablesealing material, preferably, metal which has been rendered molten.Solder may be employed for this purpose; by solder is meant an alloy oftin and lead; higher fusing point brazing or welding 11 metals may beemployed, such as an alloy embodying copper and zinc, silver solder orthe like. The preferred manner of uniting the elements where theycontact with each other is that of employing the so-called copperhydrogen welding process. This comprises utilizing copper suitably"located so that when the structure is subjected to coppermeltingtemperature in a reducing environment, for example, such as hydrogen,the copper becomes molten, runs in between the contacting surfaces, andupon cooling effectively unites the elements. Where copper-coatedferrous metals are employed, for example, the copper coatings becomewelded together and also alloy with the ferrous metal, forming a weldedperfectly fluid-tight joint having very great structural strength almostequal to that of the ferrous metal itself. In this connection it ispointed out that it is unnecessary to pre-coat the core element withcopper since the copper will flow in between surfaces fitted extremelytightly together and, in fact, it is practically impossible to have twosurfaces so tightly fitted that the copper will not flow therebetween.Where sheets or plates of ferrous metal such as low carbon steel andcoated with copper are utilized, the trough formations can be made by astamping operation and the entire core welded together to form a verystrong unit. Moreover, the copper coatings become a1- loyed to the steelstock and uniformly distributed A thereover, so that the entire unitboth inside and out is corrosion-resistant. This copper welding process,from a broad standpoint, is known to those versed in the art.

A radiator thus constructed has been found to of this invention, that isto say, the coefficient of thermal conductivity in heat unitstransferred per unit of time, per unit of area, per unit of temperaturedifferential, exceeds the K value of other known radiator structures,some as high as about 100%, and another as high as about 50%. The mostefllcient radiator of the known types which were tested was exceeded ineiiiciency by the pres! removes considerable heat so that at the frontside the efficiency may be relatively high, but since the air is'warmedby this action, the efficiency of the radiator at the rear side isrelatively low. As a result the depth of these radiators is limited froma practical standpoint. In a radiator comprising a series of tubesrunning through fin plates, or having fins attached thereto, there is amarked diiferential between the efiiciency at the front and rear sidesof the radiator. In the cellular type of radiator in which the streamsof water passing therethrough are of a width sub stantially equal to thedepth of the radiator, allowing for requisite metal thickness and finarea, the differential of the efficiency at the front and rear sides isstill marked.

With a construction embodying the present invention and as describedabove, the water flows from the top of the radiator to the bottom of theradiator in a general vertical path by passing therethrough in amultiplicity of streams. Each stream, however, as it passes through thechambers, has a movement through each chamber which is generallyhorizontal extending substantially through the depth ofthe radiator. Themovement of each stream may be termed that of a horizontal, alternatelyreversed path. A stream of water flows through one chamber, say from thefront of the radiator to the rear and down to the next lower chamber,and then horizontally through that chamber from the rear to the front,and so on through the entire structure. Therefore, the water which is atone instant at the rear of the radiator is at the next instant at thefront of the radiator so that all the water passing through the deviceis subjected to substantially the same cooling effects. In radiators ofknown types, wherein a series of tubes are usedwith some tubes behindthe others, the water in the rear tubes is entirely disassociated fromthe water in the front tubes, and such water in the rear tubes issubjected only to slight cooling-effects. The same thing is true,generally, in a cellular type of radiator where a wide stream passesthrough the radiator, because the portion of the stream near the rear ofthe radiator is not subjected to eflicient cooling action. As explainedabove, this is'not true of radiators embodying the present inventionwherein the entire body of water is subjected to the same coolingeffect.

Moreover, in a radiator embodying the present invention a certain amountof agitation or turbulence is given to the streams of water as the samepass from one chamber to another through the relatively sharp bends atthe connecting ends of the chambers. In addition, it will be observedthat the heat which enters the end walls 3 and 4, the side walls 5 and6- and bottoms 7 may be conducted directly along these walls to the finareas 10, 11 and 12, and where the plates are copper coated, theheat-may be conducted directly along the coated surfaces as the copperaffords an excellent heat conductor. By refer-. ring to Fig. 4 andconsidering the plate member with the trough second from the top, theheat may be conducted directly to the fin portions on this plate;however, some of the heat may bridge the joint between this plate andthe next lower plate and be dissipated in the fin portions of the nextlower plate. Furthermore, the bottoms of the troughs constitute internalfins of relatively large area which are in direct contact with the waterin the streams both above and below them, and therefore constituteeffective means for absorbing heat from within the streams andconducting it out to the radiating fins 10, 11 and 12.

The increased efliciency obtained with struc tures embodying the presentinvention makes it possible to obtain a given heat transfer effect witha smaller unit, which is generally desirable inorder to obtain theadvantages of decreased amount of material, weight and size. Moreover,in the case of automotive vehicles this decrease in size is important inthat it permits redesign of the front end of such vehicles along streamlines. Heretofore stream-lining the front end of a vehicle such as anautomobile has been very difficult because of the large frontal radiatorarea required to provide suflicient cooling capacity. With the increasedefficiency and decreased size obtained by the present invention, thishandicap to stream-lining is greatly reduced. Moreover, these advantagesare obtained simultaneously with the provision of a radiator which is ofinherent mechanical strength, not subject to development of leaky jointsor corrosion either inside or out, and particularly well adapted formanufacture in large quantities.

In the specification and in some of the claims it is stated that thefluid passes through the device generallyin a vertical direction with ahorizontal flow to the streams. It will be understood that the termsvertical and horizontal are employed in a relative sense only todescribe the operation of the devices illustrated, and are not to beconstrued as limiting the use of structures embodying the invention inany way. Moreover, it will be understoodthat the invention is notlimited to radiators, strictly speaking, and that the term radiator whenused in the appended claims is intended to include the structure definedwhether used as a radiator or condenser or for other similar purposes.

A radiator incorporating the invention may be made of one or morecastings. This is shown in Fig. 16; the casting may comprise a header70, a header '71, and an intermediate section having chambers 12separated by shelf-like members 73 constructed to provide connectingapertures between chambers as illustrated at '14. The shelf lid like.members are preferably inclined to provide for gravity flow. Integralfins v may be on the casting. A number of such castings may be connectedtogether to form a single radiator structure and as illustrated in Fig.17, the header members 70 may be connected by means of a flanged bushing76 and a nut 77 screwed onto one end of it. In making the casting coreholes may appear where necessary, and they may be closed or plugged inany suitable manner. By way of illustration, two of such coreholes areshown in Fig. 16, the same being plugged as at 18.

What is claimed is:

l. A core structure for a heat transfer device comprising, a pluralityof superimposed metal plates, each plate having formed therein a numberof trough-like depressions defined by side walls, end walls, and abottom wall, said plates being disposed in superimposed relation withthe troughs interfitting, the bottoms of the interfitting troughstogether with the side and end walls of the troughs cooperating todefine fluid chambers, the bottom of each trough having an aper turetherein near one end, and juxtapositioned troughs having their aperturedends respectively disposed near opposite ends of the said chambers, thebottom of each trough being inclined downwardly from its closed end toits apertured end to provide a gravity flow through the transfer device.

2. A heat transfer device comprising, a plurality of metal plates, eachplate having formed therein a number of trough-like depressions definedby side walls, end walls, and a bottom wall, said plates being disposedin a vertical superimposed relation with troughs of adjacent platesinterfitting, the bottoms of interfitting troughs being spaced from eachother and defining, together with the side and end walls, fluidchambers, the bottom of each trough having an aperture therein near oneend only, and juxtapositioned troughs having their apertured endsrespectively disposed near opposite ends of the said chambers, headermeans over the top and bottom plates for conducting fiuid to and fromthe several troughs in these plates, whereby thefiuid passes through thetransfer device in a general vertical direction and in a plurality ofstreams running through the apertures and chambers, said chambersproviding a horizontal flow for the streams.

3. A heat transfer device comprising, a plurality of metal plates, eachplate having formed therein a number of trough-like depressions definedby side walls, end walls, and a bottom wall, said plates being disposedin a vertical superimposed relation with troughs of adjacent platesinterfitting the bottoms of interiitting troughs being spaced from eachother and defining, together with the side and end walls, fluidchambers, the bottom of each trough having an aperture therein near oneend, and juxtapositioned troughs having their apertured endsrespectively disposed near opposite sends of the said chambers, headermeans over the top and bottom plates for conducting fluid to and fromthe several troughs in these plates, whereby the fiuid may pass throughthe transfer device in a general vertical direction and in a pluralityof streams running through the apertures and chambers, said chambersproviding a horizontal flow for the streams, the bottoms of the troughsbeing inclined downwardly from their closed ends to their open endswhereby to provide a gravity flow through the heat transfer device.

.4. A heat transfer device comprising a pluralat least one trough-likerasaasa ity of metal plates each having trough-like depressions thereinoi tapering form, said troughs being relatively long and each having anaperture through its bottom atone end only, alternate plates beingreversed end for end, and a plurality of said plates being disposed insuperimposed relation with the troughs interfitting, the bottoms ofinterfitting troughs defining fluid chambers with an aperture at eachend, whereby to provide a plurality of tortuous fluid passagewaysthrough the plates, plate members disposed over the end plates of thesaid superimposed plates and providing header chambers, and all of saidplates being united one to another at contacting portions by sealingmaterial.

5. A radiator core for transferring heat from one fluid to another andthrough which a current of air or the like is adapted to be passed inthe direction of the depth of the radiator, comprising a plurality ofmetal plates each having depression therein which is relatively long andnarrow, each trough having an aperture in its bottom near one end only,said plates being disposed in superimposed relation with the troughsinterfitting, the walls and bottoms of the troughs defining chambers forthepassage of fluid therethrough with each chamber having an aperturenear one end for connecting into one adjacent chamber and an aperturenear its opposite end for connecting into another adjacent chamber, saidchambers having their long dimensions extending substantially in thedirection of the depth of the radiator whereby a fluid passing throughthe radiator is directed through interconnecting chambers in a streamwhich traverses substantially the depth of the radiator with a reversedirection of flow in alternate chambers, each plate having portionsprojecting from a trough-like depression and constituting fin areas forcontact with the current of air.

6. A radiator core for transferring heat from one fluid to another andthrough which a current of air or the like is adapted to be passed inthe direction of the depth of the radiator, comprising a plurality ofmetal plates each having at least one trough-like depression thereinwhich is relatively long and narrow, each trough having an aperture inits bottom near one end, said plates being disposed in superimposedrelation with the troughs interfitting, the walls and bottoms of thetroughs defining chambers for the passage of fluid therethrough witheach chamber having an aperture near each end for connecting intoadjacent chambers, said chambers having their long dimensions extendingsubstantially in the direction of the depth of the radiator whereby afluid passing through the radiator is directed through interconnectingchambers in a stream which traverses substantially the depth of theradiator with a reverse direction of flow in alternate chambers, eachplate having portions projecting from a trough like depression andconstituting fin areas for contact with the current of air, each troughhaving side and end walls of substantially uniform depth and the bottomof each trough being inclined substantially from its closed end to itsapertured end whereby to provide a gravity flow for the fluid.

'7. A radiator core for transferring heat from one fluid to another andthrough which a current of air or the like is adapted to be passed inthe direction of the depth of the radiator, comprising a plurality ofmetal plates each having at least one trough-like depression thereinwhich is relatively long and narrow, each trough having an aperture inits bottom near one end, said plates being disposed in superimposedrelation with the troughs interfitting, the walls and bottoms of thetroughs defining chambers for the passage of fluid therethrough witheach chamber having an aperture near one end for connecting into anadjacent chamber and an aperture near its opposite end for connectinginto another adjacent chamber, said chambers having their longdimensions extending substantially in the .direction of the depth of theradiator whereby a fluid passing through the radiator is directedthrough interconnecting chambers in a stream which traversessubstantially the depth of the radiator with a reverse direction of flowin alternate chambers, each plate having portions projecting from atrough-like depression and constituting fin areas for contact with thecurrent of 'air, each aperture in the bottom of a trough having an areafor the flow of fluid therethrough which substantially corresponds tothe mean flow area of the chambers.

8. A radiator core for transferring heat from one fluid to another andthrough which a current of air or the like is adapted to be passed inthe direction of the depth of the radiator, comprising a plurality ofmetal plates each having at least one trough-like depression thereinwhich is relatively long and narrow, each trough having any aperture inits bottom near one end, said plates being disposed in superimposedrelation with the troughs interfitting, the walls and bottoms of thetroughs defining chambers for the passage of fluid therethrough witheach chamber having an aperture near each end for connecting intoadjacent chambers, said chambers having their long dimensions extendingsubstantially in the direction of the depth of the radiator whereby afluid passing through the radiator is directed through interconnectingchambers in a stream which traverses substantially the depth of theradiator with a reverse direction of flow in alternate chambers, eachplate having portions projecting from a trough-like depression andconstituting fin areas for contact with the current of air, each troughhaving side and end walls of substantially uniform depth and the bottomof each trough being inclined substantially from its closed end to itsapertured end whereby to provide a gravity flow for the fluid eachaperture in the bottom of a trough having an area for the flow of fluidtherethrough which substantially corresponds to the mean flow area ofthe chambers.

9. A radiator for transferring heat from one fluid to another andthrough which a current of air or the like is adapted to be passed inthe direction of the depth of the radiator, comprising a plurality ofmetal plates each having a single trough-like depression therein whichis relatively long and narrow, each trough having an aperture in itsbottom near one end only, a plurality of said plates being disposed insuperimposed relation to form a tier of plates with the troughsinterfitting and alternate plates reversed end to end, the walls andbottoms of the interfitting troughs defining chambers for the passage offluid therethrough with each chamber connecting at opposite ends withadjacent chambers and each chamber having its long'dimension extendingsubstantially in the direction of the depth of the radiator, a pluralityof tiers of said plates being disposed side by side, header means at thetop and at the bottom of said tiers,- whereby fluid passing through theradiator from one header to another is divided into streams each flowingthrough a series of interconnected chambers of a tier of plates, andeach stream traversing substantially the depth-ofthe radiator in flowingthrough the chambers with reverse direction of flow in alternatechambers, each plate having porfluid to another and through which acurrent of air or the like is adapted to be passed in the direction ofthe depth of the radiator, comprising a plurality of metal plates eachhaving a single trough-like depression therein which is relatively longand narrow, each trough having an aperture in its bottom near one endonly, a plurality of said plates being disposed in superimposed relationto form a tier of plates with the troughs interfitting and alternateplates reversed end for end, the walls and bottoms of the interfittingtroughs defining chambers for the passage of fluid therethrough witheach chamber connectingv at opposite ends with adjacent chambers andeach chamber having its long dimension extending substantially in thedirection of the depth of the radiator, a plurality of tiers of saidplates being disposed side by side, header means at the top and at thebottom of said tiers, whereby fluid passing through the radiator fromone header to another is divided into streams each flowing through aseries of interconnected chambers of a tier of plates, and each streamtraversing substantially the depth of the radiator in flowing throughthe chambers with reverse direction of flow in alternate chambers, eachplate having portions constituting fin areas for contact with thecurrent of air and projecting from the troughlike depression therein,said plates being united r and sealed together-to close said chambers bysealing material.

11. A radiator core for transferring heat from one fluid to another andthrough which a current of air or the like is adapted to be passed inthe directionof the depth of the radiator, comprising a plurality ofmetal plates each having at least one trough-like depression thereinwhich is relatively long and narrow, each trough having an aperture inits bottom near one end only, alternate plates being reversed and-saidplates being disposed in superimposed relation with the troughs rinterfitting and united by melted sealing metal, the walls and bottomsof the interfitting troughs defining chambers for the passage of fluidtherethrough, each chamber having its long dimension extendingsubstantially in the direction of the depth of the radiator wherebyfluid passing through a series of interconnected chambers traversessubstantially the depth of the radiator with reverse direction of flowin alternate chambers, each plate having portions projectingsubstantially from the open side of the trough therein constituting finareas for contact with the current of air passing through the radiator.

12. A core structure for a heat transfer device comprising walls of heatconductive material forming a plurality of superposed chambers elongatedin a horizontal direction, each pair of adjacent chambers having acommon intermedipassing downwardly through said chambers flowshorizontally through the individual chambers and oppositely inconsecutive chambers, and substantially horizontal radiating finsextending from said walls.

14. A core structure for a heat transfer device comprising walls forminga plurality of vertical structures each elongated in one horizontaldirection to substantially the depth of the device and each divided byspaced generally horizontal walls into a plurality of superposedhorizontal chambers extending substantially the depth of the device,said walls forming the bottoms of said chambers and adjacent chambershaving apertures at opposite ends of their bottoms whereby each of aplurality of streams passing downwardly through one of said structuresflows horizontally back and forth through consecutive chambers, and finsextending from said walls in horizontal planes adjacent each chamber andforming passages through which a second fluid flows in contact with saidfins and the side walls of the chambers.

15. A core structure for a heat transfer device comprising a pluralityof assembled metal members rigidly secured together and shaped to formone or more rows of superposed chambers elongatedin a horizontaldirection, each pair of adjacent chambers having a common intermediatewall and alternate intermediate walls having apertures at opposite endsof their bottoms, the bottom wall of each chamber being inclined towardits apertured end, said members providing outwardly extending finportions adjacent each chamber and in substantially horizontal planes.

16. A core structure for a heat transfer device comprising a pluralityof assembled members of copper-coated ferrous metal shaped to form avertical structure elongated in a horizontal direction and divided byspaced generally horizontal partitions into a plurality of superposed,elongated horizontal chambers, adjacent partition walls being aperturedat opposite ends, said members providing outwardly extending radiatingfins adjacent ,each chamber, and the copper coatings being weldedtogether at contacting portions of said members, whereby a welded,fluidtight and copper-coated core structure is provided. j

17. A core structure for a heat transfer device comprising a pluralityof assembled members of copper-coated ferrous metal, said membersforming a plurality of vertical rows of superposed elongated horizontalchambers, the bottom walls of adjacent chambers being oppositelyinclined and having apertures at their lowermost ends,

said members also providing horizontal radiating fins adjacent andintegral with each chamber, the contacting portions of said membersbeing welded together whereby a welded, fluid-tight and copper-coatedcore structure is provided.

18. A core structure for a heat transfer device comprising walls of heatconductive material il,985,$839l forming a plurality of superposedchambers elongated in a horizontal direction and radiating finsextending outwardly therefrom in substantially horizontal planes, thebottom wall of each.chamber being depressed out of its normal plane intoarcuate formation and the bottom walls of adjacent chambers beingoppositely inclined and apertured at their lower ends.

19. A=core structure for a heat transfer device comprising walls of heatconductive material forming a plurality of superposed. chamberselongated in a horizontal direction and radiating fins extendingoutwardly therefrom in substantially.

horizontal planes, the bottom wall of each chamber being depressed outof its normal planeinto arcuate formation and the bottom walls ofadjacent chambers being oppositely inclined and apertured at their lowerends, said apertures extending the entire width of the bottoms of saidchambers.

20. A core structure for a heat transfer device comprising walls of heatconductive material forming a plurality of superposed, elongated,horizontal chambers and radiating fins extending outwardly therefrom insubstantially horizontal planes, adjacent chambers having apertures atthe opposite ends of their bottoms whereby a fluid passing downwardlythrough said chambers flows horizontally'back and forth throughconsecutive chambers, said chambers each extending substantially theentire depth of the device, said apertures having a flow areasubstantially equal to the mean flow area of said chambers.

21. A core structure for a-heat transfer device comprising walls of heatconductive material forming a plurality of superposed, elongated,horizontal chambers and radiating fins extending outwardly therefrom,the bottom walls of adjacent chambers having apertures at opposite endsand being inclined downwardly toward their apertured ends, certain ofsaid apertures having a flow area less than the mean flow area of saidchambers in order to constitute restric-. tion.

22; In a radiator core, the combination of a plurality of metal plateseach having a troughlike depression formed therein, said troughs beingof increased depth toward one end thereof whereby the bottom wallsthereof are inclined and said bottom walls being apertured at their deepends, said plates being assembled with said troughs interfitting andwith interfitting troughs reversed end for end to form chambers with thebottoms ,of adjacent chambers oppositely inclined, said'plates formingradiating fins integral with the side and end walls of said chambers.

23. A core structure for a heat transfer device comprising walls of heatconductive material forming a plurality of superposed chambers elongatedin a horizontal direction and each chamber extending from the front tothe rear of the core structure, each pair of adjacent chambers having acommon intermediate wall adjacent chambers having apertures at oppositeends of their bottoms so that a fluid passes through said

